Emergency stop system for a non rail-based motor vehicle

ABSTRACT

A steering system with a steering adjustment unit, based on the “steer by wire” concept, with an additional system for an automatic emergency stopping maneuver is provided. In situations that cannot be controlled by the driver, preset data from a preset or storage arrangement are transmitted to a braking system and a steering adjustment unit, with the vehicle then being braked and steered according to the preset data.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a steering system for a non-railbornemotor vehicle with a motor-driven steering adjustment unit whichcontrols the steerable wheels of a vehicle, and which is actuated by asteering control arrangement on the basis of a comparison betweensignals indicating the actual steering angle value generated by anactual value transmitter actuated by the steerable wheels of the vehicleand signals indicating the nominal steering angle value generated by anominal preset value unit.

In conventional motor vehicles, the manual steering mechanism, usually asteering wheel, is forcibly linked to the steerable wheels of thevehicle so that the steering wheel and the steerable wheels of thevehicle always perform analogous adjustment movements. Servo units alsoensure that the manual forces which need to be exerted on the steeringwheel remain small.

Steering systems are now, however, being developed in which the manualsteering mechanism and the steerable wheels of the vehicle are linkedonly functionally via a control system. The steerable wheels of thevehicle or parts linked to them actuate an actual steering angletransmitter. The steering mechanism acts upon a nominal steering angletransmitter. A controller compares the nominal value signals from thenominal value transmitter with the actual value signals from the actualvalue transmitter and actuates a motor-driven adjustment unit linkedwith the steerable wheels of the vehicle to adjust their steering angleon the basis of the comparison. In this concept, also known as“steer-by-wire”, the basic advantage is that, in addition to the controlof the manual steering mechanism by the driver, many other parameterscan be taken into account when the adjustment unit is actuated.Moreover, there is no need for a steering column, which essentiallypresents a danger during vehicle collisions.

This kind of steering system is particularly well suited to automaticsteering interventions, for example, to minimize the effects of a crosswind or the like on the desired path of the vehicle.

German Patent Document DE 198 41 914 A1 discloses an automatic steeringsystem which, while the vehicle is traveling in one direction (e.g.,forward), can register essential data for the route covered and thesteering maneuvers performed such that the vehicle can subsequentlytravel in a reverse direction (e.g., backward) automatically in the pathcovered before when traveling in the first direction.

The present invention provides increased safety in driving situationsthat can no longer be driver-controlled with a steering system of thetype described above.

This is achieved by equipping the vehicle with a system for automaticbraking intervention, a system for recognizing driving conditions beyondthe control of the driver and a default or storage arrangement withpreset data for an emergency stopping maneuver, and by causing thesteering adjustment unit as well as the system for automatic brakinginterventions to automatically follow the preset emergency data in oneof the driving conditions beyond the control of the driver.

The present invention makes an automatic emergency vehicle stoppingmaneuver possible by constantly collecting steering data suitable forsuch a maneuver and keeping it ready to control a system existing in thevehicle for automatic braking intervention and the motor-driven steeringadjustment unit in a manner suitable for emergencies.

System components already existing in the vehicle and basicallywell-known can be advantageously used to implement the presentinvention.

Thus, for example, systems for automatic braking intervention arebasically well-known and are already standard in many vehicles in order,for example, to assist steering maneuvers initiated by the driver byselective braking intervention on individual wheels or to reduce thedanger of the vehicle spinning out when cornering at speed. Such systemsare basically suitable, when appropriately controlled, for bringing avehicle automatically to a stop in an emergency stopping maneuver.

The same applies to the motor-driven steering adjustment unit necessaryin steering systems of the type described above which, according to thepresent invention, like the system for automatic braking interventions,only has to follow the commands for the emergency stopping path duringthe emergency stopping maneuver.

In addition to the steering and braking systems, other systems can alsocome under automatic control when emergency maneuvers are performed,e.g., there can be intervention in the spring/shock absorber systems ofa chassis, in engine control systems and/or a vehicle's drivetransmission control systems or the like.

The result is that the vehicle can therefore be accelerated ordecelerated in an emergency maneuver by appropriate preset data in alongitudinal, transverse and/or up-and-down direction.

The present invention is suitable for multiple emergency situations,including emergencies caused both by the driver and by the vehicle.

In the event that extreme faintness on the part of the driver isregistered by an appropriate sensor system, a vehicle according to theinvention can stop automatically. If, on the other hand, there is thehighly unlikely occurrence of a break in the signal path between thesteering adjustment unit and the controller, the storage arrangement isstill available with preset data for the emergency stopping maneuver.This storage arrangement is, according to a preferred embodiment of thepresent invention, arranged in parallel to the signal path between thecontroller and the steering adjustment unit and separate from thecontroller.

According to one embodiment of the present invention, the preset datafor the emergency stopping maneuver are constantly updated by means ofan appropriate sensor system so that when an emergency actually occursan optimal stopping maneuver is performed automatically.

In this connection, the sensor system mentioned above can, for example,constantly evaluate the data from a navigation system (GPS) in order tostore the street layout for a driving stretch that is sufficient for astopping maneuver. There can also be means provided for recognizingother vehicles and obstacles, so that in an emergency stopping maneuverthe last state of the vehicle's surroundings can always be taken intoaccount before the emergency occurs, and in the case of movingobstacles, i.e., particularly for other vehicles registered by thesystem, their last determined direction and speed are recorded as neededso that the last determined situation can be extrapolated to a futureperiod of time.

Reference is made hereinafter, with respect to preferred features of theinvention, to the claims and the following explanation of the diagramwhich is used to describe in detail an especially preferred form of theinvention.

BRIEF DESCRIPTION OF THE DRAWING

The single FIGURE shows a block diagram of the steering system of theinvention.

DETAILED DESCRIPTION

A vehicle, not shown in detail, possesses front and rear wheels 1, withthe steerable front wheels being linked by motor-driven steeringadjustment unit 2 for their steering adjustment. An actual valuetransmitter 3, whose signals give the actual value of the particularsteering angle, and a pressure and force measuring device 4, whosesignals reflect the steering forces developed between steerable frontwheels 1 and steering adjustment unit 2, are assigned to front wheels 1and steering adjustment unit 2.

Steering wheel 5, operated by the driver, is linked to manual forceadjuster 6, which serves to change the hand forces applied on thesteering wheel. The torques developed between manual force adjuster 6and the steering wheel are recorded by means of torque meter 7. Steeringwheel 5 also acts together with angle measuring unit 8 whose signalsreflect the steering angle desired by the driver.

The inputs to control device 9 come from actual value transmitter 3,pressure and force measuring device 4, torque meter 7 and anglemeasuring unit 8. Steering adjustment unit 2 and manual force adjuster 6are connected to the output side. Control device 9 can also have aninput connection from another sensor system 10 which allows recording ofthe driving condition parameters of the vehicle, such as, for example,yawing movements and lateral accelerations of the vehicle, as well ascrosswind effects.

In normal driving situations, the signal from angle measuring unit 8,which reflects the steering angle preset by the driver on steering wheel5, is processed as the nominal baseline steering angle value. If sensorsystem 10 is present, its signals can be used to modify the nominalbaseline value to take the particular special driving situation or theparticular recorded driving condition parameters into account in thenominal steering angle value. This nominal steering angle value iscompared with the actual steering actual value recorded by actual valuetransmitter 3. Based on the nominal value-actual value comparison,control device 9 actuates steering adjustment unit 2. As a result theactual steering angle value therefore follows the nominal steering anglevalue.

The steering forces produced between steering adjustment unit 2 andsteerable front wheels 1 and recorded by pressure and force measuringdevice 4, or the signals representing these forces, are processed bycontrol device 9 as the nominal preset value for actuating manual forceadjuster 6 so that control device 9 is able, by corresponding actuationof manual force adjuster 6, to produce a force appropriate to theparticular driving situation which opposes the turning action ofsteering wheel 5. The actual forces produced between manual forceadjuster 6 and steering wheel 5 in each case are recorded by torquemeter 7 and “reported” to control device 9.

Basically, control device 9 can, if necessary, also simulate, by meansof manual force adjuster 6, sudden twists or other effects occurringwith the conventional steering systems.

According to the present invention, the vehicle also possesses preset orstorage arrangement 11 which allows an automated vehicle stoppingmaneuver without driver involvement to be carried out in extreme dangersituations.

This preset or storage arrangement 11 has parallel output connections tocontrol device 9 and steering adjustment unit 2. A system 12 for anautomatic braking intervention, which can control wheel brake units 15for each wheel or each axle in order to slow or stabilize the vehicle,is also connected to the output side of preset or storage arrangement11. When steering adjustment unit 2 and system 12 are correspondinglyactuated for automatic braking intervention, preset or storagearrangement 11 can therefore perform a vehicle stopping maneuver.

On the input side, preset or storage arrangement 11 is connected withtheoretically any system, but especially sensor systems whose signalsare suitable or useful for ascertaining an optimal stopping path.

Accordingly, preset or storage arrangement 11 can constantly communicatewith control device 9 so as to be able to take into account all datapresent there, and especially the signals of the sensors working withcontrol device 9. Additionally or alternatively, preset or storagearrangement 11 can also communicate directly with the aforementionedsensors.

Furthermore, preset or storage arrangement 11 can be connected to sensordevices 13 to record the particular driving path. An example of such adevice is a navigation system which can represent both the geographicposition of the vehicle and the course driven by the vehicle in the formof corresponding signals. Another example is a detection system forvehicles driving ahead or obstacles in the driving direction.

Another system 16 is preferably provided for recognition of drivingconditions beyond the control of the driver. This system 16 cantherefore recognize with sensors (not shown here) whether the driver haslost control of the vehicle due to technical problems or outsidecircumstances such as, for example, loss of driver consciousness. In theexample shown, system 16 is integrated into steering control arrangement9 and monitors the communication between steering control arrangement 9and the steering adjustment unit. The system can also be connected to asensor system for monitoring the driver, such as, for example, adrowsiness warning device.

All data from systems 9, 13 and 16 communicating with the preset orstorage arrangement are processed as control data for an optimalemergency stopping maneuver and stored, with these data being constantlyupdated. As a rule, control data are therefore stored at differentpoints in time for emergency stopping maneuvers that vary from oneanother. The data of no longer current emergency stopping maneuvers areconstantly erased or removed from the corresponding data storage.

In normal driving situations, preset or storage arrangement 11 is notactive.

Only if an extremely dangerous condition occurs, for example if a breakin the signal path between control device 9 and steering adjustment unit2 is detected, do the control data present in preset or storagearrangement 11 become active for an emergency stopping maneuver; theyare then sent to steering adjustment unit 2 and to system 12 forautomatic braking intervention. The vehicle therefore performs asteering and braking maneuver until the vehicle comes to a stop.

1-7. (canceled)
 8. A steering system for a non-railborne motor vehiclewhich a motor-driving steering adjustment unit which controls steerablevehicle wheels and is actuated by a steering control arrangement on thebasis of a comparison between actual steering angle signals from anactual value transmittal actuated with the steerable vehicle wheels andnominal steering angle signals from a nominal value preset unit, whereinthe vehicle includes a system for automatic braking intervention, asystem for recognizing driving conditions beyond a driver's control andpreset or storage arrangement with preset data for an emergency stoppingmaneuver, and wherein the steering adjustment unit and the system forautomatic braking interventions follow the preset data.
 9. The steeringsystem according to claim 8, wherein the preset data are constantlyupdated by sensors which sense operating and path conditions.
 10. Thesteering system according to claim 9, wherein the sensors can detectobstacles and/or other vehicles.
 11. The steering system according toclaim 9, wherein the sensor systems includes a navigation system whichprovides data on a particular section of the path ahead.
 12. Thesteering system according to claim 8, wherein the system for recognizingdriving conditions beyond the driver's control can detect loss ofconsciousness of a driver.
 13. The steering system according to claim 8,wherein the preset or storage arrangement becomes active when there is abreak in a signal path between the steering adjustment unit and thesteering control arrangement.
 14. The steering system according to claim8, wherein the preset or storage arrangement contains only command datafor an emergency stopping path.
 15. A motor vehicle, comprising: amotor-driven steering adjustment unit, which controls steerable vehiclewheels; a steering control arrangement, which actuates the motor-drivensteering adjustment unit on the basis of a comparison between actualsteering angle signals from an actual valve transmitter actuated withthe steerable vehicle wheels and nominal steering angle signals from anominal value preset unit; a system for automatic braking intervention;a system for recognizing driving conditions beyond a driver's control;and a storage arrangement, which stores preset data for an emergencystopping maneuver. wherein the steering adjustment unit and the systemfor automatic braking interventions follow the preset data.
 16. Thesteering system according to claim 15, wherein the preset data areconstantly updated by sensors which sense operating and path conditions.17. The steering system according to claim 16, wherein the sensors candetect obstacles and/or other vehicles.
 18. The steering systemaccording to claim 16, wherein the sensor systems includes a navigationsystem which provides data on a particular section of the path ahead.19. The steering system according to claim 15, wherein the system forrecognizing driving conditions beyond the driver's control can detectloss of consciousness of a driver.
 20. The steering system according toclaim 15, wherein the preset or storage arrangement becomes active whenthere is a break in a signal path between the steering adjustment unitand the steering control arrangement.
 21. The steering system accordingto claim 15, wherein the preset or storage arrangement contains onlycommand data for an emergency stopping path.